While watching the rather lovely Boyzone at 20 pop-extravaganza on ITV1 this week, I was pushed to ponder how boy bands these days never truly split up. Much like the formula of their greatest hits, they tend to pause, shift to a key change, then carry on triumphantly. Boyzone – currently celebrating their 20th year since they were just a twinkling pound sign in Louis Walsh’s eye – are a great example of our new appetite for boyband longevity.

Once, as we saw via archive footage, Ronan and the gang were skinny-limbed, bashful teens trotting through lyrics about deep eternal love while wearing expressions that only ever shouted, “I miss my mother’s cooking”. Privately, they called their first tour, we learned, “the window ledge tour”, as it was little more than an excursion around Ireland in a Transit van with stop-offs at village halls to play to four bemused girls and the bloke in charge of locking up. Sometimes no real stage, just young lads stood flapping their arms to a backing track on a window ledge.

Nowadays Boyzone are hulking great blokes. They’re the sort of men you’d trust with erecting a flatpack shed or putting their face into the back of a toilet cistern. Boyzone are a man band. Men awash with tattoos and excess testosterone and the odd wrinkle from early morning daddy-duties. If I was in pop-feminist mode I could splash a few thousand words here about the current crop of boybands – Take That, 5ive, Backstreet Boys – turning to man bands and retaining their original audience, and how this fits with women being societally permitted nowadays to be sexually lascivious into a later stage of their lives. Instead I’ll merely say that in the 1960s, a gang of 37-year-old women buying tickets to scream very rude suggestions and throw knickers at someone like Ronan Keating in a stadium would have been most off-colour. In 2014 – during Boyzone’s 17 date stadium tour – many, many children will be going to school breakfasted on Maltesers and Kia-Ora Tropical because Mummy had a night off watching Boyzone. This is a good thing. OK, maybe not if it’s your own mother and she shows up in the crowd footage of ITV1’s Boyzone at 20 doing big pointy arms in the air dancing to “Picture of You” wearing a Per Una shrug and looking like she may have had a full bottle of Lambrusco Rosato. But a good thing for women in general.

In fact, it’s difficult to do anything other than like Boyzone in their current stage of life. They’re a lesson to us all about friendship and humility. I’m sure there are people reading this who weren’t quite in the demographic to lap up a lilting Cat Stevens’ “Father and Son” cover in 1995, but nowadays there’s something oddly spiriting about Ronan, Mikey, Shane and Keith in a line being interviewed by Dannii Minogue about 20 years on pop’s playing fields. Like all boybands, at the height of their fame they were worked like pack ponies until they couldn’t stand the sight of each other. This is unavoidable. It will happen to One Direction, as it happened to 911, precisely as it happened to 5ive. Candidly, we learned that Ronan Keating pulled the plug on Boyzone and Shane Lynch admitted he hated him for it. Hated him. It would be difficult, I feel, for Shane to feel anything less than hatred as cherubic blonde Ronan skipped off into the distance with his glorious solo career, his Richard Curtis soundtrack soaraway hit and his big bag of New Radicals’ Gregg Alexander pixie dust to sprinkle all over future singles. Keith Duffy ended up behind the bar in Coronation Street. Mikey Graham studied sound technology. Mikey and Shane didn’t speak for years after a row over exhaust pipes. Ronan never quite stopped being a pop prince. These things are bound to rub. But then something awful happened and none of this really matters.

The loss of Stephen Gately is rawly imprinted on all of Boyzone’s faces. Stephen is not gone, he’s still here, he still a member of the band, they say. It’s hard to dispute. Stephen isn’t history. Their grief may have aged but it is still bold, still fresh. Footage shows Stephen in the prime of life, beautiful, cheeky-faced, hard-bodied, ambitious. Ronan speaks of his fury about the injustice of this ending. Stephen had never looked better, never been happier, never had more to live for, never been more in love. And at just that point Stephen’s life suddenly stopped. This death – as his friends sit in a row, full of life, dripping with bloke-next-door charm– seems all the more preposterous, unfair, unfeasible.

The band takes to the stage and spins through some of the older hits like “No Matter What”. And a new one, “Love Will Save The Day”. Ronan does most of the singing. The others do a lot of meaningful staring, the odd point and hand flourish. It’s only pop music but it makes people happy. Life is brief. Making people happy should never be underrated.